Method and apparatus for mounting filaments



' 'H. P. CLAUSEN ma'rnon u) APPARATUS FOR MQUNTING mpmnn'rs Filed Feb.5, 1920 Patented Jan. 6, 1925.

UNITED STATES 4 1,522,286 PATENT OFFICE.

' HENRY ROLAUSEN, OF MAMARO'NEC K, NEW YORK, ASSIGNOR TO WESTERNELECTRIO" COMPANY, INCOIQPORATED, OF NEW YORK, N. Y., A CORPORATION OFNEW YORK.

METHOD AND APPARATUS FOR MOUNTING FILAMENTS.

Application filed February 3, 1920. Serial No. 356,051.

To all whom it may concern:

Be it known that I, HENRY P. OLAUsnN, a citizen of the United States,residing at Mama-roneck, in the county of Westchester and State of NewYork, have invented certain new and useful Improvements in Methods andApparatus for Mounting Filaments, of which the following is a full,clear,-

concise, and exact description.

My present invention relates to electrlcal devices and more particularlyto electrical lamps or vacuum tubes and it has for its object to improvein the manner of mounting the filaments used in these tubes,particularly when the space between electrodes is small. Theimprovements have reference to properly tensloning the filament in a newand inexpensive way and to so connecting its ends to the lead-in wiresthat the attachinents may be conveniently made with freedom exteriorlyof the grid structure and the parts then positioned properly between thegrids with greater ease than heretofore. To these and other ends theinvention resides in certain improvements and combinations of parts allas will be hereinafter more fully described, the'novel features beingpointed out in the claims at the end of the specification.

In the drawings: Figure 1 is a fragmentary side view of a partiallyfinished filament constructed and mounted in accordance with myinvention;

Figure 2 is a similar view. of the finished filament of my inventionFigure 3 is anenlarged fragmenta detail view illustrative of the variouswires, and v Figure 4 is a side view partlybroken away of a vacuum tube'of a type in which a mode of joining I my Invention may be utilized toadvantage.

Similar reference numerals throughout the several viewsindicate the sameparts, Referring to the drawings, 1 indicates the tube and 2 the laviteor similar insulating block at the head thereof having dependv inglateral wires 3 that 4 and 5 and a central hook support the grids 6supporting the intermediate portion or apexof the looped filament 7.The, ends of the filament are connected to the respective lead-in wires8' issuing from the stem In the practice of inypresent invention,

I construct my leadein wires 8 of comparw mediate of their length I weldor otherwise 0 secure to each of them one end of a short tensioning'wire 10. This wire is referably a light weight, hard drawn Wire thetension of which is not easily affected byheat, for instance,molybdenum. The other end of this tension wire is welded or clamped toan end of the filament '7 and at the time the stem assembly iscompleted, including the grid and filament, this point of'attachmentlies outside of the grid as before and as shown in Figure 1. I then usethe projecting end portions 11 of the lead-in wires 8 to manipulatethemby an inward bend so that theycarrythe ends of the filament to thedesired'positions inside of the grids as shown in Figure 2. In doing so,the spring connecting wires 10 are .also carried inwardly and are placedunder tension as shown in the same figures, so that the desired tensionis communicated to the filament as it hangs upon its central hooksupport 6.- Great latitude is attained in bending the lead-in wire 8back and forth to cause the spring 10 tobe placed in any desiredpositionand the projecting end 11 of the wire forms a very convenienthandle for efi'ectingthis bending operation with the greatest ease, itbeing unnecessary to enter an additional tool of any kind in the narrowspace between the two sides of the the outer end of the element 10. Thewire 10 may be flattened at a point such as 13 in the manner shown sothat the end of the wirehas little or-no lateral give.

It will be noted that my invention does not call for a, spring support.t the top nu have shown an enlarged l i where thefilament is fastened tothe top of and I thus permit the use the stem assembly. I place thesprings at the bottom where rthe leading in wires are located butovercome the difiicultyof using the molybdenum wire as 'aleading-in wireby Welding it to the comparatively heav wire of any esired appropriatematerial as a leading-in wire that may prove more satisfactory for thispurpose than would molybdenum or similar wlre.

Another feature of importance is that if the leading-in wire is, say,nickel or copper, a material reduction in cost will be obtained throughits bein unnecessary to use more than a, very smal amount-of molybdenumwire to secure the desired tension upon the filament. Other wire such assteel or nickel, could be used, particularly in the formation shown inFi 'ure 3, and have a minimum amount of side play, thus keeping thefilament in a central position between the two sides ofv the grid.Extreme variations in temperature result in inch in the length of thefilament and in the practice of my invention, this variation iscompletely absorbed by the tensioniug spring 10 when properly adjusted.

What is claimed is: I

1. A method of mounting vacuum tube filaments which comprises securingin the tube a lead-in wire substantially longer U to intermediateportions of a than its required final length, attachlng an end of thefilament to an intermediate portion of said wire, manipulating the freeend of said wire to give the filament its position and tension, and thencutting ofi the excess portion of said wire.

2. A method of mounting vacuum tubefilaments, which comprlses'attachin apair of resilient wires to the ends ofthe lament, attaching'said wiresat a substantial angle air of lead-in and-bending'sa-id lead-1n wires toflex wires,

WIIYQS and thereby. tension said said resilient filament. o

3. A method "offlmounting vacuum tube filaments between other electrodesthereof which comprises attaching connecting wires 7 other electrodesand wires in the tube, attac ing a pair of some cases m a van ation ofapproximately one-sixteenth of an.

menace to intermediateportions of the lead-in wires after the otherelectrodes are assembled, attaching the ends of the filament to theconnecting wires at points exteriorly of the then manipulating the freeends of the lead-in wires to carry the attached ends of the filamentbetween the other electrodes.

.4. A method of mounting filaments in vacuum tubes of the type having anelectrode surface at each side of the filament,

a pair of plastic resilient wires to said plastic wires and to the endsof said filament with said ends extending outside the boundaries of saidsurfaces, and bending said plastic wires to position the filament withinsaid boundaries and to tension the filament.

5. The combination with a vacuum tube filament and a support for oneportion thereof, of a support for another portion thereof comprising awire of plastic material secured in the tube, and a resilient wireattached which comprises securin to said plastic wire and to said otherportion, said plastic wire being bent to a position to flex saidresilient wire whereby tension is applied to said filament.

6. The combination with a vacuum tube filament and a central supporttherefor, of a pair ofrelatively heav leadin wires of plastic material,and a light resilient wire connecting each end of the filament to alead-in wire, said lead-in wires being bentto positions to flex saidresilient wires whereby tension is applied to said filament.

7. The combmation'with a vacuum tube filament and a central supporttherefor, of

a pair of relatively heavy lead-in wires of plastic material, and a ghthard drawn spring wire not easi affected by 'heat connected to eachlead-in wire and to an end of the filament, said lead-in wires beingbent to positions toflex said sprin wires whereby tension -'isapplied'to said filament.

In .witness wher'eofll hereunto subscribe my name this 28th day ofJanuary, A. D 1920.

nann r. cmnsnn.

